This Allergic Diseases Center proposal deals with two aspects of allergic inflammation: (1) the functions of eosinophils and (2) the production of IgE antibodies. We plan to isolate granules from eosinophils, to purify from them the material composing the central crystalline core, and to investigate the physicochemical and biological properties of this material. As another approach to the function of the eosinophil we will isolate Charcot-Leyden crystals. If these crystals are derived from the central crystalline core, our studies may be considerably simplified by preparation of crystals and analysis of their properties. Concurrent with these studies we will determine whether any patterns of abnormality of immunoglobulins and complement characterize patients with pronounced eosinophilia. We also describe experiments to determine whether immunotherapy induces a state of partial immunological tolerance in the IgE and IgG classes in patients with ragweed hay fever. Prior studies indicate that the activity of IgE wanes during immunotherapy and we have found that when IgE is low in treated patients IgG also tends to be low. Furthermore theoretical considerations and some experimental observations suggest that IgE antibodies may have a high-affinity for antigen. If so, then immunotherapy may lower their affinity and we describe methods to measure the affinity of IgE antibodies. Finally we describe experiments to study the effects of corticosteroids on the rises of IgE antibodies following the ragweed pollination season. BIBLIOGRAPHIC REFERENCES: Gleich, G. J., Loegering, D. A., Mann, K.G. and Maldonado, J. E.: Comparative properties of the Charcot-Leyden crystal protein and the major basic protein from human eosinophil granules. J. Clin. Invest. 57:633, 1976. Gleich, G. J. and Jacob, G. L.: Immunoglobulin E antibodies to pollen allergens accounts for high percentages of total immunoglobulin E protein. Science. 190:1106, 1975.